Pneumatic tires in recent years have widthwise grooves arranged in center and shoulder areas of a tread to ensure their braking and driving performance. Such a tread pattern is called a traction pattern. Pneumatic tires with a traction pattern have challenges to maintain snow braking and wet performance of the tire. Further, such pneumatic tires tend to have an increased tire rolling resistance due to a large number of widthwise grooves arranged thereon.
Patent Document 1 discloses a known technology of a conventional pneumatic tire that is related to the present invention. The conventional pneumatic tire has wide grooves including a pair of main grooves that are provided on its tread outer surface to be away from an equatorial plane thereof toward tread edges by a distance 0.41 times to 0.75 times as large as half of a tread width W. Further, the tread outer surface is segmented to a center area positioned in a center portion between the paired main grooves in a width direction, and shoulder areas positioned between the center portion of the paired main grooves and the both tread edges. In the conventional tire in which a negative ratio is reduced to nearly equal values for the center area and each of the shoulder areas from when the tire is new to when it gets 75% wear, a reduction rate of negative ratio at the center area from when the tire is new to when it gets 75% wear is reduced.
Patent Document 1: Japanese Patent Application Laid-open No. H11-34614